Hi Fellas. Been almost a year since I've been in here. Nice changes. Anyway, I am by far a transmission person, so I come to you with this.

1990 GMC Sierra 1500 with 5.7 ,manual transmission,4x4. Just bought it and when shifting thru the gears it got stuck in I think 3rd, but the shifter feels like its in neutral position. I have tried to put it in other gears but it wont. As soon as i release the clutch it tries to take off in 3rd. When i tried other gears i hear a sound like its trying to grind. The transmission,transfer case,clutch assembly and slave cylinder have all been replaced. If stuck in 3rd, is there any way to get it working properly again without replacement or complete tear down? Thanks guys

Update: I pulled shifter out to find it was partially stuck in 3rd. I was able to get it into neutral. I used a small pry bar to slide each gear in and out and they all go in and out fine and each are working. Could this be that it may have been sticky from sitting for a long time? I also found that whoever installed the tranny only used 2 out of 4 bolts when they installed the shifter. I'm thinking/hoping this may have let the shifter not seat properly allowing it to slip out of slider. I dont know. Thanks in advance for any tips/help you can offer.

This has been one of the major problems in handicap vans where it is very hard to change the gears in right timing. I also see that some times when the vehicle is not in neutral it starts moving it self and that is really a big problem even when the hand break is pulled on. When the clutch is release it tries to take of in 3rd and while changing the gear from there it takes out very irritating sound. Now I also have come to know that the shifter not seat properly allowing it to slip out of slider. Thanks for this wonderful information appreciated it.